Railroad tie

ABSTRACT

An improved railroad tie comprises a monolithic elongate tie body divided into a pair of end sections and a narrow mid section interconnecting the pair of end sections. Further, the top surface of each end section divided into a proximal and distal surface sections interconnected by a rail seat section whereon a rail is fixedly mounted. The proximal and distal surface sections slope downwards, in opposing directions, as they extend longitudinally from the rail seat section and connect the top surface of the mid section and the extreme lateral edge of the top surface of the end section respectively. The mid section is of uniform trapezoidal cross-section. The railroad tie further comprises a plurality of steel rebars cast within the tie body.

BACKGROUND Technical Field

This invention relates to railway engineering and more particularly torailroad ties.

Concrete railroad ties are reinforced or pre-stressed concrete beamsgenerally configured to have a uniform and trapezoidal cross-section.Steel bars are typically embedded into a railroad tie for reinforcementpurposes. The top surface at each end of the railroad tie is fitted witha rail attachment means (called fastening system). The base of therailroad tie is wider than its top surface so as to have theties-ballast contact pressure less than the allowable amounts. Althoughthese typical railroad ties are effective in carrying out their purpose,they are not optimally designed and hence not cost-effective. Moreparticularly, although, the central section of the railroad tie is notsubjected to the same amount of load as the end sections of the railroadtie, nonetheless, the former is “invested” with the same amount of rawmaterial (concrete). This superfluous material on the central sectionnot only makes the railroad tie expensive but also bulky and heavy.Furthermore, the amount of steel bars used in the conventional ties isnot optimum.

Therefore, in the light of the above discussion, there is a need in theart for an improved railroad tie that has an optimal design, and isthereby cost-effective. Such a railroad tie should also possess allmechanical and structural characteristics required by the internationalstandards.

SUMMARY

The present invention is an improved railroad tie which aims to addressthe above mentioned need: to have an optimal structural configurationand thereby, being cost-effective. The railroad tie is a longitudinalbeam which comprises a monolithic elongate tie body divided a pair ofend sections interconnected by a mid section. The top surface of eachend section includes a rail seat section whereon a rail sits. The midsection is narrower and is of uniform trapezoidal cross-section.Compared to the typical concrete railroad ties discussed above, therailroad tie of the present invention consumes lesser amount of rawmaterial, i.e., concrete and steel, owing to the narrow structuralconfiguration of the mid section. Steel bars are cast within therailroad tie for pre-stressing. The improved railroad tie, whilepossessing all the mechanical and structural characteristics required byinternational standards, is lighter, less bulky, and essentiallycost-effective compared to traditional concrete railroad ties. Also,less ballast is needed for the railroad tie since its structuralconfiguration causes a more uniform stress distribution of the pressureon the ballast and thereby less stress concentration on and within theballast layer.

The other objects and advantages of the embodiments herein will becomereadily apparent from the following detailed description taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of the perspective view of the railroad tieaccording to the present invention.

FIG. 2 is an illustration of the front view of the railroad tieaccording to the present invention.

FIG. 3 is an illustration of the plan view of the railroad tie accordingto the present invention.

FIG. 4 is an illustration of the perspective view of the end section ofthe railroad tie according to the present invention.

FIG. 5 is an illustration of the plan view of the end section of therailroad tie according to the present invention.

FIG. 6 is an illustration of the perspective view of the mid section ofthe railroad tie according to the present invention.

FIG. 7 is an illustration of the sectional side view of the mid sectionof the railroad tie according to the present invention.

FIG. 8 is an illustration of the front view of the railroad tie withdimensions in accordance with the present invention.

FIG. 9 is an illustration of the plan view of the railroad tie accordingto the present invention.

FIG. 10 is an illustration of the sectional side view of the mid sectionof the railroad tie according to the present invention.

FIG. 11 is an illustration of the side view of the railroad tieaccording to the present invention.

FIGURES Reference Numerals

-   10 . . . Railroad tie-   12 . . . Tie body-   14 . . . End section-   16 . . . Mid section-   18 . . . Proximal surface section-   20 . . . Distal surface section-   22 . . . Rail seat section-   24 . . . Lateral groove-   26 . . . Lateral ridge-   28 . . . Top surface of the mid section-   30 . . . Rebar

DETAILED DESCRIPTION

In the following detailed description, a reference is made to theaccompanying drawings that form a part hereof, and in which the specificembodiments that may be practiced is shown by way of illustration. Theseembodiments are described in sufficient detail to enable those skilledin the art to practice the embodiments and it is to be understood thatthe logical, mechanical and other changes may be made without departingfrom the scope of the embodiments. The following detailed description istherefore not to be taken in a limiting sense.

Referring to FIGS. 1 through 3, the present invention comprises arailroad tie 10, which serves as a base for railroad tracks. Therailroad tie 10 transfers the load from the track onto the ballast,whereon the railroad tie 10 is placed. The railroad tie 10 is preferablymade of pre-stressed reinforced concrete, which, compared to thecommonplace reinforced concrete, offers better compressive strength,longer life expectancy, and easier maintenance.

Still referring to FIGS. 1 through 3, the railroad tie 10 comprises amonolithic elongate tie body 12 defined by an elongate top surface, anelongate substantially flat bottom surface, a pair of opposing elongateside surfaces connecting the longitudinal edges of the top and bottomsurfaces, and a pair of opposing end surfaces connecting the lateraledges of top, bottom, and side surfaces. At any point along the lengthof the tie body, the width of the top surface is lesser than that of thebottom surface. More particularly, the tie body 12 is of a substantiallytrapezoidal cross-section at any point along the length thereof. Thistrapezoidal structural configuration of the tie body 12 helps therailroad tie 10 in uniformly distributing load from the track to theballast. The bottom surface may be coarse or may be provided withgripping indentations in order for the tie body to have traction on theballast, which helps resisting any movement of the railroad tie on theballast.

The length of the tie body is divided into three sections, viz., a pairof end sections 14, and a mid section 16 interconnecting the pair of endsections. Referring to FIGS. 4 and 5, the top surface of each endsection can be divided into three sections, viz., a proximal surfacesection 18, a distal surface section 20, and a rectangular rail seatsection 22 interconnecting the proximal and distal surface sections 18and 20. The rail seat section 22 receives a rail attachment meansthereon. Each lateral edge of the rail seat section 22 terminates in alateral groove 24 of uniform cross-section. A lateral ridge 26 ofuniform cross-section extends from the lateral edge of each groove 24.

Still referring to FIGS. 4 and 5, the proximal surface section 18interconnects the lateral edge of a ridge 26 and the lateral edge of thetop surface of the mid section 16 wherein, the width of the lateral edgeof the proximal surface section 18 extending from the ridge 26 isgreater than that of the opposing lateral edge of the proximal surfacesection 18 connecting the top surface of the mid section 16. Theproximal surface section 18 slopes downward as it extends from the ridge26 towards the mid section 16. The distal surface section 20interconnects the lateral edge of the other ridge 26 and the top edge ofthe of the corresponding end surface wherein, as in the earlier case,the width of the lateral edge of the distal surface section 20 extendingfrom the ridge 26 is greater than that of the opposing lateral edge ofthe distal surface section 26 connecting the end surface. The distalsurface section 20 also slopes downward as it extends from the ridge 26towards the mid section 16. The slope of the initial portions of theproximal and distal sections 18 and 20 longitudinally proceeding fromthe ridges 26 is steeper compared to that of the latter portions of theproximal and distal surface sections 18 and 20 joining the mid section16 and the end surface respectively.

Referring to FIGS. 6 and 7, the mid section 16 of the tie body 12 isnarrow compared to the pair of end sections 14, i.e., the height andwidth of the mid section 16 is lesser than that of the pair of endsections 14. The mid section 16 of the tie body 12 is of uniformsubstantially trapezoidal cross-section. The width of the rail seatsection 22 is greater than that of the top surface 28 of the mid section16.

Referring to FIG. 7, the railroad tie 10 further comprises a pluralityof elongate steel rebars 30 embedded longitudinally into the tie body12. Preferably, two sets of rebars 30 are cast within the tie body 12.Each set includes three rebars 30 that are horizontally aligned. Thesets are placed such that each rebar 30 of a set is vertically alignedwith a rebar 30 from the other set.

While there is a myriad of possibilities as to, to what dimensions therailroad tie 10 is to be made, FIGS. 8 through 11 depict the preferreddimensions in centimeters. The Table depicts the tolerances for therailroad tie 10 made of the preferred dimensions.

The foregoing description of the specific embodiments will so fullyreveal the general nature of the embodiments herein that others can, byapplying current knowledge, readily modify and/or adapt for variousapplications such specific embodiments without departing from thegeneric concept, and, therefore, such adaptations and modificationsshould and are intended to be comprehended within the meaning and rangeof equivalents of the disclosed embodiments. It is to be understood thatthe phraseology or terminology employed herein is for the purpose ofdescription and not of limitation. Therefore, while the embodimentsherein have been described in terms of preferred embodiments, thoseskilled in the art will recognize that the embodiments herein can bepracticed with modification within the spirit and scope of the appendedclaims.

Although the embodiment herein are described with various specificembodiments, it will be obvious for a person skilled in the art topractice the invention with modifications. However, all suchmodifications are deemed to be within the scope of the claims.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the embodimentsdescribed herein and all the statements of the scope of the embodimentswhich as a matter of language might be said to fall there between.

TABLE Dimensional Characteristics Tolerances Railroad tie lengthimmediately after stage of conveying ±6 mm pre-stressed formCross-sectional dimension of the railroad tie ±3 mm Position of thegeometric center of the rebars compared ±3 mm to the geometric center ofconcrete section Cover of the rebars ±5 mm Straightforwardness oflateral direction of railroad tie ±6 mm Concavity or convexity of railseat section in any direction ±0.5 mm Inward slope of rail seat section1 in ± 400 Deflection and slope of rail seat section along the 1 in 100longitudinal length Distance between central axis of rail seat sectionand the −0.25 mm location of imposing connection system force onrailroad ±0.75 mm Change range of width on sleeper Max 6 mm

1. A railroad tie comprising: (a) an monolithic elongate tie bodydefined by an elongate top surface, a substantially flat elongate bottomsurface, a pair of opposing elongate side surfaces connecting thelongitudinal edges of the top and bottom surfaces, and a pair ofopposing end surfaces connecting the lateral edges of the top, bottomand side surfaces, the tie body longitudinally divided into: (i) a pairof end sections, the top surface of each end section longitudinallydivided into: (aa) a rail seat section whereon a rail is fixedlymounted; (bb) a proximal surface section sloping downwards as it extendslongitudinally from a lateral edge of the rail seat section; and (cc) adistal surface section interconnecting the other lateral edge of therail seat section and the top edge of the corresponding end surface, thedistal surface section sloping downwards from the rail seat section tothe end surface; and (ii) a mid section interconnecting the pair of endsections, the mid section being narrower than the pair of end sections;and (b) a plurality of elongate rebars cast within the tie bodylongitudinally wherein the rebars are horizontally and verticallyaligned.
 2. The railroad tie of claim 1 wherein, the tie body is made ofpre-stressed concrete.
 3. The railroad tie of claim 1 wherein, therebars are made of steel.
 4. The railroad tie of claim 1 wherein, alateral groove extends from each lateral edge of each rail seat section,the groove is of uniform cross-section, the lateral edge of the grooveterminating in a lateral ridge of uniform cross-section, the proximaland distal surface sections extending from the lateral edges of therespective ridges.
 5. The railroad tie of claim 1 wherein, the rail seatsection is rectangular.
 6. The railroad tie of claim 1 wherein, the midsection is of uniform trapezoidal cross-section.
 7. The railroad tie ofclaim 1 wherein, at any point along the length of the tie body, thewidth of the top surface is lesser than that of the bottom surface. 8.The railroad tie of claim 1 wherein, the width of the top surface of themid section is lesser than that of the rail seat section.
 9. Therailroad tie of claim 1 wherein, the width of the proximal surfacesection extending from the lateral edge of the rail seat section isgreater than that of the proximal surface section connecting the topsurface of the mid section.
 10. The railroad tie of claim 1 wherein, thewidth of the distal surface section extending from the lateral edge ofthe rail seat section is greater than that of the distal surface sectionconnecting the end surface.
 11. The railroad tie of claim 1 wherein, theslope of the proximal and distal surface sections is steeper as theyextend downwardly from the respective lateral edges of the rail seatsection; the slope being steeper till a portion along the lengththereof.
 12. The railroad tie of claim 1 wherein, the rebars are dividedinto a plurality of sets wherein, each set comprises a plurality ofhorizontally aligned rebars, and each set is disposed one below another.13. The railroad tie of claim 12 wherein, the plurality of setscomprises two sets.
 14. The railroad tie of claim 12 wherein, each setcomprises three rebars.
 15. A railroad tie comprising: (a) an monolithicelongate tie body made of pre-stressed concrete, the tie body defined byan elongate top surface, a substantially flat elongate bottom surface, apair of opposing elongate side surfaces connecting the longitudinaledges of the top and bottom surfaces, and a pair of opposing endsurfaces connecting the lateral edges of the top, bottom and sidesurfaces, the tie body longitudinally divided into: (i) a pair of endsections, the top surface of each end section longitudinally dividedinto: (aa) a rectangular rail seat section whereon a rail is fixedlymounted; (bb) a proximal surface section sloping downwards as it extendslongitudinally from a lateral edge of the rail seat section; and (cc) adistal surface section interconnecting the other lateral edge of therail seat section and the top edge of a corresponding end surface, thedistal surface section sloping downwards from the rail seat section tothe end surface; and (ii) a mid section interconnecting the pair of endsections, the mid section being of uniform cross-section, the midsection being narrower than the pair of end sections, the mid sectionbeing of uniform trapezoidal cross-section; and (b) a plurality ofelongate steel rebars cast within the tie body longitudinally whereinthe rebars are divided into a plurality of sets wherein, each setcomprises a plurality of horizontally aligned rebars, each set isdisposed one below another such that the rebars are vertically alignedtoo.